Scientists construct eruption machine
The days of using baking soda and vinegar are over for a group of Massey University scientists, who have started simulating genuine volcanic eruptions on the Turitea campus.
The Volcanic Risk Solutions team yesterday let media in to watch them set off an eruption in the university's old boiler room using a 15m tall machine colloquially named the Tower of Doom.
The machine is designed to create a pyroclastic flow eruption - essentially an avalanche of ash hurtling down a hillside at speeds that have yet to be fully explained by physics.
Close to 5 tonnes of specially collected volcanic particles from an eruption at Lake Taupo 2000 years ago are compressed in the simulator and then gas is added until the pressure becomes too great and the ash forces its way out and down a specially designed ramp at close to 100kmh.
Professors Shane Cronin and Gert Lube are leading the world-first research project.
"With the way the machine is we can create all sorts of eruption patterns," Dr Lube said.
"This was probably more of an eruption that you would see in Taranaki.
"It's also similar to Mt Merapi in Indonesia, which is probably the most explosive and active volcano in the world, and what we had at Tongariro in 2012".
High-speed cameras that can measure an individual particle's journey once out of the simulator were being used, which will help communities with hazard planning, he said.
"We can't record an actual eruption because that would be like measuring into a nuclear blast, but in a controlled environment like this we can.
"The volcanoes which are mainly associated with lava are actually quite predictable but the ones that are more prone to pyroclastic flows can be much more violent and much less predictable.
"In an actual eruption they can reach speeds of 300kmh and 800 degrees Celsius.
"That sort of stuff burns people to death and tears down trees and buildings over a long distance," Dr Lube said.
Prof Cronin said construction of the simulator began three years ago and it could help prove why the flows defy current scientific thinking.
"Physics would suggest they should stop closer to where they actually do ,so we know there is something that is making them go further.
"The hypothesis is that there's a sort of air cushion created and the particles are riding on top of that to a certain extent.
"We were expecting flows of 9m per second but we are actually getting more like 25m per second which is a big difference."
Watching the eruption for the first time was volcanologist Greg Valentine from Buffalo University in New York.
"This is unique, the group here at Massey are on the cutting edge of everything we are doing," he said.
To know how particles in a flow travel was crucial for the safety of people around volcanoes, Dr Valentine said.
"Computer models can predict but in order for us to know those models have a high degree of accuracy, we have to test the models in action.
"This is really the first work that can realistically test them," Dr Valentine said.
"Obviously we are never going to be able to get to the scale mother nature does but most of the basic parameters are covered by a flow this size."
Dr Lube said the group was doing eruption regularly and experimenting with different temperatures.
One experiment involved heating the ash to 300C and then triggering it from outside the door.